unit_tests: fix block reward test using post hard fork settings
unit_tests: fix block reward test using post hard fork settings

This would fail, as the post hard fork settings would yield
different data, and the test expects pre hard fork data.

eiabea/bitmonero,eiabea/bitmonero,ranok/bitmonero,eiabea/bitmonero,ranok/bitmonero,ranok/bitmonero,eiabea/bitmonero,ranok/bitmonero,eiabea/bitmonero,ranok/bitmonero,ranok/bitmonero,eiabea/bitmonero